Social Media Use and Internalizing Symptoms in Clinical and Community Adolescent Samples: A Systematic Review and Meta-Analysis.

Importance: In response to widespread concerns about social media's influence on adolescent mental health, most research has studied adolescents from the general population, overlooking clinical groups. Objective: To synthesize, quantify, and compare evidence on the association between social media use and internalizing symptoms in adolescent clinical and community samples. Data Sources: Peer-reviewed publications from MEDLINE, Web of Science, PsycInfo, and Scopus (initially reviewed in May 2022 and updated in October 2023) and preprints from Europe PubMed Central (February 2023) published in English between 2007 and 2023. Study Selection: Two blinded reviewers initially identified 14 211 cross-sectional and longitudinal studies quantifying the association between social media use and internalizing symptoms, excluding experimental studies and randomized clinical trials. Data Extraction and Synthesis: PRISMA and MOOSE guidelines were followed, pooling data using a random-effects model and robust variance estimation. The quality of evidence was assessed using the Quality of Survey Studies in Psychology Checklist. Main Outcomes and Measures: Articles were included if they reported at least 1 quantitative measure of social media use (time spent, active vs passive use, activity, content, user perception, and other) and internalizing symptoms (anxiety, depression, or both). Results: The 143 studies reviewed included 1 094 890 adolescents and 886 effect sizes, 11% of which examined clinical samples. In these samples, a positive and significant meta-correlation was found between social media use and internalizing symptoms, both for time spent (n = 2893; r, 0.08; 95% CI, 0.01 to 0.15; P = .03; I2, 57.83) and user engagement (n = 859; r, 0.12; 95% CI, 0.09 to 0.15; P = .002; I2, 82.67). These associations mirrored those in community samples. Conclusions and Relevance: The findings in this study highlight a lack of research on clinical populations, a critical gap considering public concerns about the increase in adolescent mental health symptoms at clinical levels. This paucity of evidence not only restricts the generalizability of existing research but also hinders our ability to evaluate and compare the link between social media use and mental health in clinical vs nonclinical populations.

The importance of individual beliefs in assessing treatment efficacy.

In recent years, there has been debate about the effectiveness of treatments from different fields, such as neurostimulation, neurofeedback, brain training, and pharmacotherapy. This debate has been fuelled by contradictory and nuanced experimental findings. Notably, the effectiveness of a given treatment is commonly evaluated by comparing the effect of the active treatment versus the placebo on human health and/or behaviour. However, this approach neglects the individual's subjective experience of the type of treatment she or he received in establishing treatment efficacy. Here, we show that individual differences in subjective treatment - the thought of receiving the active or placebo condition during an experiment - can explain variability in outcomes better than the actual treatment. We analysed four independent datasets (N = 387 participants), including clinical patients and healthy adults from different age groups who were exposed to different neurostimulation treatments (transcranial magnetic stimulation: Studies 1 and 2; transcranial direct current stimulation: Studies 3 and 4). Our findings show that the inclusion of subjective treatment can provide a better model fit either alone or in interaction with objective treatment (defined as the condition to which participants are assigned in the experiment). These results demonstrate the significant contribution of subjective experience in explaining the variability of clinical, cognitive, and behavioural outcomes. We advocate for existing and future studies in clinical and non-clinical research to start accounting for participants' subjective beliefs and their interplay with objective treatment when assessing the efficacy of treatments. This approach will be crucial in providing a more accurate estimation of the treatment effect and its source, allowing the development of effective and reproducible interventions.

Neuromodulation is a type of intervention that relies on various non-invasive techniques to temporarily stimulate the brain and nervous system. It can be used for the treatment of depression or other medical conditions, as well as the improvement of cognitive abilities such as attention. However, there is conflicting evidence regarding whether this approach has beneficial effects. Most studies aiming to assess the efficiency of a treatment rely on examining the outcomes of people who received the intervention in comparison to participants who undergo a similar procedure with no therapeutic effect (or placebo). However, the influence of other, 'subjective' factors on these results ­ such as the type of intervention participants think they have received ­ remains poorly investigated. To bridge this gap, Fassi and Hochman et al. used statistical modeling to assess how patients' beliefs about their treatment affected the results of four neuromodulation studies on mind wandering, depression and attention deficit hyperactivity disorder symptoms. In two studies, participants' perceptions of their treatment status were more strongly linked to changes in depression scores and mind-wandering than the actual treatment. Results were more nuanced in the other two studies. In one of them, participants who received the real neuromodulation but believed they received the placebo showed the most improvement in depressive symptoms; in the other study, subjective beliefs and objective treatment both explained changes in inattention symptoms. Taken together, the results by Fassi and Hochman et al. suggest that factoring in patients' subjective beliefs about their treatment may be necessary in studies of neuromodulation and other interventions like virtual reality or neurofeedback, where participants are immersed in cutting-edge research settings and might therefore be more susceptible to develop beliefs about treatment efficacy.

Lack of Sample Diversity in Research on Adolescent Depression and Social Media Use: A Scoping Review and Meta-Analysis.

Research on whether social media use relates to adolescent depression is rapidly increasing. However, is it adequately representing the diversity of global adolescent populations? We conducted a preregistered scoping review (research published between 2018 and 2020; 34 articles) to investigate the proportion of studies recruiting samples from the Global North versus Global South and assess whether the association between social media and depression varies depending on the population being studied. Sample diversity was lacking between regions: More than 70% of studies examined Global North populations. The link between social media and depression was positive and significant in the Global North but null and nonsignificant in the Global South. There was also little evidence of diversity within regions in both sampling choices and reporting of participants' demographics. Given that most adolescents live in the Global South and sample diversity is crucial for the generalizability of research findings, urgent action is needed to address these oversights.

The role of gesture as simulated action in reinterpretation of mental imagery.

In two experiments, we examined the role of gesture in reinterpreting a mental image. In Experiment 1, we found that participants gestured more about a figure they had learned through manual exploration than about a figure they had learned through vision. This supports claims that gestures emerge from the activation of perception-relevant actions during mental imagery. In Experiment 2, we investigated whether such gestures have a causal role in affecting the quality of mental imagery. Participants were randomly assigned to gesture, not gesture, or engage in a manual interference task as they attempted to reinterpret a figure they had learned through manual exploration. We found that manual interference significantly impaired participants' success on the task. Taken together, these results suggest that gestures reflect mental imaginings of interactions with a mental image and that these imaginings are critically important for mental manipulation and reinterpretation of that image. However, our results suggest that enacting the imagined movements in gesture is not critically important on this particular task.